Burner for electric ranges



June 29 1926.

R. H. M INNES BURNER FOR ELECTRIC RANGES Filed June 24, 1925 Patented June 29, 1926.

U NIZFED S 'PA TES PATENT QE-FIGE.

COMPANY, LIMITED, 0F HAMILTON, CANADA.

BURNER non ELECTRIC RANGES.

Application filed June 24, 1925.

This invention relates to improvements in burners for. electric ranges or other similar electric heating devices such as hot plates, stands and the like.

These burners are usually round or disc shaped and manufactured of refractory insulating material such as porcelain. UsuaL ly in such burners there is one or more grooves having a tortuous course throughout the upper surface of the burner, and in this groove the helical resistance wire is strung. It is desirable that the resistance wire be elevated from the bottom of this groove so as to provide ventilation beneath the wire, and such ventilation and air circulation is essential for the maximum efficiency of the burner as porcelain absorbs a certain proportion of the heat radiated from the resistance wire wherever the same touches it without ventilation.

Warmed air rises. Therefore the warmed air beneath an elevated resistance wire carries with it to the cooking utensil resting upon the burner the warmth which would, if the resistance wire rested upon the bottom of the groove, be rapidly absorbed by the porcelain.

Different devices have been used to thus elevate the resistance wire, but all of these devices created another undesirable result. They offset the resistance wire from the center of the groove and threw it against either wall, with the result that there was another contact with the porcelain, and consequently there was absorption of heat at another point.

Although, in the latter occurrence, there remained what appeared to be free circulation or ventilation, it has been found by exhaustive and careful experiment and test that the efliciency of the burner was appreciably less than when the resistance wire was centrally disposed in the groove and an equal air space on each side of it between the walls of the groove. This is probably because the warmed air, when rising at the side of the groove in which the resistance wire was resting, adhered somewhat to that side of the wall during its upward flow and was therefore partially absorbed thereby.

An important object of this invention is, therefore, to provide means in a groove in an electric urner to elevate the resistance Serial No. 39,302.

wire from the bottomof the groove and at the same time to maintain the resistance wire centrally of the walls of the groove.

A second important object is to provide a device of the class described which will be durable, simple, effective, and inexpensive to manufacture.

These, together with other objects, may

be attained by the construction of a burner as will be hereinafter more fully described, illustrated in the accompanying drawing, and pointed out in the claim hereunto annexed.

Referring to the drawing:

Figure 1 is a plan view of a broken portion of an electric burner constructed in accordance with this invention and showing the resistance wire only in fragments in order to fully illustrate the important feature of the invention, which otherwise, would be obscure; and,

Figure 2 is a cross-sectional elevation of the structure shown in Figure 1.

Similar reference characters refer to corresponding parts throughout both views.

This invention is applicable to any type of electric burner having a helically coiled heating resistance wire confined in one or more grooves in the upper surface thereof; hence, there is shown on the drawing a round type burner as an example.

The refractory insulation material, such as porcelain, forms the body of the burner. indicated on the drawing by the numeral 10, and the resistance wire is indicated by 11. This resistance wire is strung in the groove 12.

As a means to elevate the resistance wire 11 from the bottom of the groove 12 there is provided a pair of spaced ribs or rails 14 formed on the bottom of the groove, and the resistance wire is adapted to rest upon these rails.

It will be noted that the said rails are of inverted V shape in cross-section, and slightly rounded at the apex and at their point of convergence with the main body, in order to eliminate possibility of chipping.

These rails are spaced so that the distance between the seats is less than the diameter of the coils of the resistance wire. Thus the resistance wire spans these rails finding its t ra sea and t w l e ted that there is open space beneath the said wire between the rails, between the rails and the Walls of the grooves, and between the lateral portions of the wire and the walls of the grooves.

It will also be observed that the resistance wire can touch only these rails, and that on all sides of the rails there is air to convey upwardly to the cooking surface of the burnor all the warmth it receives from the resistance wire.

There has thus been produced a simple and efi'icient device of the class described and for the purpose specified.

Having now fully described the present resistance wire in an elevated position in the groove and spaced from the sides of the groove.

In testimony whereof I have afiixed my 25 signature.

ROBERT H. MAOINNES. 

